This invention relates to fuel tanks, and particularly to fuel tanks with internal fuel pumps.
Prior techniques for mounting fuel pumps within a vehicle fuel tank include the use of a freely floating pump which is mounted by a bracket to the top wall of the fuel tank as shown in U.S. Pat. No. 3,101,771. Thus, the top wall of the tank can be assembled with the fuel pump and mounting brackets and thereafter assembled with the bottom portion of the tank by use of screws. The free-floating fuel pump tends to oscillate, particularly when the tank has a low fluid level, and can thereby generate undesired noises. In addition, the distance between the intake opening of the pump and the bottom of the tank, which determines whether full utilization is made of tank capacity, depends upon a large number of tolerances, so that it is possible that part of the tank content cannot be used in order to prevent interference of parts. In order to achieve full utilization of the tank and make the distance between the suction opening of the pump and the tank bottom very small using prior arrangements, it would be necessary to construct all elements of the fuel tank with very tight tolerances.
German patent disclosures Nos. 2,440,904 and 2,505,740 show tank arrangements wherein a fuel pump is secured using an elastic intermediate layer in a recess in the tank bottom, and provide with an outlet line that runs from the fuel pump in the form of a rigid pipe to a cover which is connected on the upper tank wall. While this arrangement provides a fixed position for the pump, which enables full utilization of the tank contents, it is necessary to maintain tolerances between the cover position and the tank bottom in order that the parts can be assembled together in the proper configuration. In particular, even a very small change in the height of the tank will require a different length of rigid fuel outlet pipe. Further it should be noted that when the lid is fastened to the top wall of the tank, movements will occur which will be opposed by the pump and its bracing to the tank bottom. The use of a relatively simple one turn cap for a cover is not possible with the arrangement shown by the prior publication.
It is therefore an object of the present invention to provide a new and improved fuel tank which includes a fuel pump, and is capable of easy assembly without the requirement for close tolerances among the various parts of the fuel pump and tank.
It is a further object of the invention to provide such an arrangement wherein noises associated with the operation of the fuel pump are not easily conveyed to the outside of the tank.
It is a still further object of the invention to provide such an arrangement which can be easily implemented in tanks of various sizes.